Method of sealing a porous block

Abstract

A block to be consolidated, which is contained in a bag made of liquid tight flexible sheet material, is enclosed in a pressure tight container with the open mouth of the bag open upwardly. While the vacuum is maintained in the container, a liquid medium is supplied into the container and around the bag until the liquid medium reaches a level lower than the level of the open mouth of the bag, after which the container is evacuated into a vacuum state, and then a fluid hardenable resin composition is fed into the bag, through its open mouth, until the block is immersed in said composition. Thereafter, the vacuum is released from the container, so that the fluid resin composition deeply penetrates into all the cavities of the block which are open to the outside, and finally the resin composition is allowed to harden, whereby a consolidated block is obtained.

We claim: 
     
       1. A method for consolidating a block of marble or other natural stone, having cavities open to the outside, comprising the following sequential steps: a. placing a block to be consolidated in a bag made of liquid-tight flexible sheet material, said bag having an open mouth;   b. enclosing said bag and said block placed therein in a pressure-tight container, with said bag having its mouth above said block and open upwardly;   c. evacuating said container into a vacuum state;   d. while said vacuum is maintained in said container, supplying a liquid into said container and around said bag until said liquid reaches a level lower than the level of said open mouth;   e. while said vacuum is maintained in said container, supplying a fluid hardenable resin composition into said container in such a manner that said fluid composition is introduced into said bag through its open mouth, until said block is immersed in said fluid resin composition;   f. while said liquid is maintained around said bag, releasing said vacuum from said container, so that said resin composition deeply penetrates into said cavities in said block; and   g. while said liquid is still around said bag, allowing said resin composition to harden in said cavities and around said block.   
     
     
       2. A method as claimed in claim 1, including the additional step of progressively regulating the level of said liquid around said bag from the time when said block is immersed in said fluid resin composition and during said deep penetration of said fluid resin composition into the cavities of said block in such manner that the level of said fluid resin composition is constantly maintained above said block. 
     
     
       3. A method as claimed in claim 1, including the additional step of condensing into ice, inside said container, any water vapor existing in said container, including that originating from said block. 
     
     
       4. A method as claimed in claim 1, including the additional step of placing said container into an overpressure state after said vacuum has been released.